The present invention relates to a sterilizing method for medical sterilization packaging and an injection pack. More particularly, the present invention relates to a method of sterilizing a medical product, e.g., a medicine-filled injector enclosed in a packaging container, by a hydrogen peroxide gas while keeping the packaged condition, which method is capable of efficiently conducting the sterilizing treatment and of surely preventing the hydrogen peroxide gas from remaining in the packaging container, and to an injection pack comprising a packaging container and a medicine-filled injector enclosed in the packaging container, which is sealed by a sterile paper and capable of mainly allowing only the sterilizing gas to penetrate therethrough, and enables the medicine-filled injector enclosed in the packaging container to be readily sterilized.
Medicine-filled injectors, have been suitably subjected to medical sterilization packaging and then distributed or marketed, as well as other disposable medical products or appliances. The medical sterilization packaging is a packaging method which comprises using a packaging container composed of a container body composed of a synthetic resin having a gas-barrier property, and a sterile paper as a lid which can allow a sterilizing gas to penetrate therethrough and can be welded to the container body, and after enclosing the medical product in the packaging container, exposing the medical product to a sterilizing gas while keeping the packaged condition, whereby an inside of the packaging container is sterilized by the sterilizing gas which is caused to penetrate thereinto through the sterile paper.
In the above-mentioned medical sterilization packaging, in order to solve the problem caused by toxicity of the sterilizing gas, it has been studied for sterilization of various medical products to use a hydrogen peroxide gas instead of ethylene oxide. However, even though any of ethylene oxide and the hydrogen peroxide gas is used, it has been inevitably required that the packaged medical products are subjected to post-treatment for removing the sterilizing gas from the inside of the packaging container, thereby eliminating an adverse influence on human bodies due to the residual harmful gas upon distribution thereof. Incidentally, the techniques concerning disinfection or sterilization using hydrogen peroxide has been described in Japanese Patent Publication (KOKOKU) No. 61-4543 (1986) (GB-A 2127692), Japanese Patent Application Laid-open (KOKAI) No. 1-121057 (1989) (EP-A 0302420) or the like. In addition, the techniques concerning medicine-filled injectors has been described in Japanese Patent Application Laid-open (KOKAI) No. 4-150868 (1992) (EP-A 0505579) or the like.
Meanwhile, in the medical sterilization packaging, in order to completely remove the sterilizing gas from the packaging container after the sterilizing treatment, it is necessary to allow the packaged medical products to stand for a considerably long period of time. The gas-removing operation has resulted in low productivity of the packaged medical products. Especially, in the case of the injection packs, since the injection packs are stacked up in multiple stages when sterilized, there arises a problem that the efficiency of penetrating the sterilizing gas through the sterile paper is deteriorated, because the surface of the sterile paper is disadvantageously covered by the container body of the upper or lower packaging container stacked. Further, in the injection packs, in view of a shape of the packaging container thereof, there has also been caused a problem that a degassing efficiency of removing the penetrated gas from an inside of the packaging container is deteriorated.
Furthermore, in the above-mentioned medical sterilization packaging, when a container composed of a polyester-based resin is used as the packaging container, the container has a high adsorptivity for the sterilizing gas, so that it becomes more difficult to remove the sterilizing gas therefrom. For this reason, there have been used many containers composed of vinyl chloride-based resins as a main component. As a result, the visibility of an inside of the container is deteriorated, and there has been further caused a problem that a chlorine gas or hydrogen chloride gas is generated upon disposal of the vinyl chloride-based resins.